HBV infection, particularly chronic HBV infection is one of the most important public sanitation problems throughout the world (Dienstag J L. Hepatitis B virus infection. N Engl J Med 2008 Oct. 2; 359(14):1486-1500). Chronic HBV infection may cause a series of liver diseases such as Chronic hepatitis B (CHB), Liver cirrhosis (LC) and Hepatocellular carcinoma (HCC) (Liaw Y F, Chu C M. Hepatitis B virus infection. Lancet 2009 Feb. 14; 373(9663): 582-592). It is reported that there are about 2 billion persons infected by HBV, and there are about 350 million persons with chronic HBV infection in the whole world now. Among these infected persons, the risk of ultimately dying of liver diseases associated with HBV infection may reach up to 15%-25%, and more than 1 million persons die of these diseases every year in the whole world (Dienstag J L., vide supra; and Liaw Y F et al., vide supra).
Currently, the therapeutic agents for chronic HBV infection may be mainly classified into Interferons (IFNs) and nucleoside or nucleotide analogues (NAs) (Dienstag J L., vide supra; Kwon H, Lok A S. Hepatitis B therapy. Nat Rev Gastroenterol Hepatol 2011 May; 8(5): 275-284; and Liaw Y F et al., vide supra). The former includes common interferon (IFN) and Peg-interferon (Peg-IFN, also termed long acting interferon), which achieve the effect of inhibiting HBV and treating CHB mainly by enhancing the overall immunocompetence of a patient; the latter mainly includes lamivudine (LMV), adefovir dipivoxil (ADV), Entecavir (ETV), Telbivudine (LdT) and Tenofovir, which inhibit the HBV replication mainly by directly inhibiting polymerase activity of HBV. For HBV infected persons (e.g. CHB patients), said agents used alone or in combination therapy have already effectively inhibited virus replication in vivo, and greatly reduced HBV DNA level; in particular, after such a treatment for 52 weeks or longer, response rate of virological response that HBV DNA level is lower than a detection limit in patients can reach 40-80% (Kwon H et al., vide supra). However, the treatment with said agents alone or in combination cannot completely clear up HBV viruses in infected persons, and the response rate of the negative conversion of HBsAg or HBsAg serological conversion (a marker indicative of complete clearance of HBV viruses in patients) is generally lower than 5% (Kwon H et al., vide supra). Therefore, it is urgent and necessary to develop novel therapeutic methods and agents capable of more effectively clearing up HBV viruses, particularly clearing up HBsAg for HBV infected patients.
It is one of the important research directions in this field to develop new agents for treating chronic HBV infection based on immunological means. Immunotherapy of chronic HBV infection is generally performed in two manners, i.e. passive immunotherapy (corresponding to medicaments in the form of antibodies, etc.) and active immunotherapy (corresponding to medicaments in the form of vaccines, etc.). Passive immunotherapy (with antibody as an example) refers to the process of administering a therapeutic antibody to a HBV infected patient and preventing naïve hepatocytes from HBV infection by antibody-mediated virus neutralization, or clearing up viruses and infected hepatocytes in vivo by antibody-mediated immune clearance, thereby achieving a therapeutic effect. Now, anti-HBs polyclonal antibodies, obtained from serum/plasma of responder immunized with hepatitis B vaccine or rehabilitee of HBV infection, i.e. high-titer hepatitis B immunoglobulin (HBIG), have been widely applied to blockage of mother-infant vertical transmission of HBV, prevention of patient with chronic HBV infection from HBV re-infection after liver transplantation, and prevention of people accidently exposed to HBV from infection. However, the therapy concerning direct administration of HBIG to HBV-infected patients (e.g. CHB patients) has no significant therapeutic effect, and HBIG is restricted in many aspects such as relatively few sources of high-titer plasma, high cost, unstable property, and potential security problems. Active immunotherapy refers to the process of administering therapeutic vaccines (including protein vaccines, polypeptide vaccines, nucleic acid vaccines, etc.), stimulating the patient with chronic HBV infection to develop cellular immunologic response (CTL effect, etc.) or/and humoral immunologic response (antibodies, etc.) to HBV, thereby achieving the purpose of inhibiting or clearing HBV. Now, there are no agents/vaccines for active immunotherapy that are definitely effective and are useful for treating chronic HBV infection yet.
Therefore, it is urgent and necessary to develop novel therapeutic methods and agents capable of more effectively treating HBV infection for HBV infected patients.
Contents of Invention
In one aspect, the invention provides an antibody or an antigen binding fragment thereof, which can specifically bind to HBsAg, comprising:
(a) one or more (e.g. 1, 2 or 3) complementarity determining regions (CDRs) of heavy chain variable region (VH) selected from the group consisting of:
(i) VH CDR1, consisting of the following sequence: SEQ ID NO: 3, or a sequence that differs from SEQ ID NO:3 by one or several substitutions, deletions or additions (e.g. 1, 2 or 3 substitutions, deletions or additions);
(ii) VH CDR2, consisting of the following sequence: SEQ ID NO: 4, or a sequence that differs from SEQ ID NO:4 by one or several substitutions, deletions or additions (e.g. 1, 2, 3, 4, 5 or 6 substitutions, deletions or additions), and
(iii) VH CDR3, consisting of the following sequence: SEQ ID NO: 5, or a sequence that differs from SEQ ID NO:5 by one or several substitutions, deletions or additions (e.g. 1, or 2 substitutions, deletions or additions);
and/or
(b) one or more (e.g. 1, 2 or 3) CDRs of light chain variable region (VL) selected from the group consisting of:
(iv) VL CDR1, consisting of the following sequence: SEQ ID NO: 6, or a sequence that differs from SEQ ID NO:6 by one or several substitutions, deletions or additions (e.g. 1, 2 or 3 substitutions, deletions or additions),
(v) VL CDR2, consisting of the following sequence: SEQ ID NO: 7, or a sequence that differs from SEQ ID NO:7 by one or several substitutions, deletions or additions (e.g. 1, 2, 3 or 4 substitutions, deletions or additions), and
(vi) VL CDR3, consisting of the following sequence: SEQ ID NO: 8, or a sequence that differs from SEQ ID NO:8 by one or several substitutions, deletions or additions (e.g. 1, 2, 3 or 4 substitutions, deletions or additions).
In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention comprises VH CDR1, VH CDR2 and VH CDR3 as defined above. In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention comprises VL CDR1, VL CDR2 and VL CDR3 as defined above. In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention comprises VH CDR1, VH CDR2, VH CDR3, VL CDR1, VL CDR2 and VL CDR3 as defined above.
In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention is humanized. In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention has a humanization degree of at least 80%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100%. In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention comprises no more than 20, no more than 15, no more than 14, no more than 13, no more than 12, no more than 11, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 2, or no more than 1 murine amino acid residues, or comprises no murine amino acid residue. In some preferred embodiments, the framework region (FR) of the antibody or an antigen binding fragment thereof according to the invention comprises no more than 20, no more than 15, no more than 14, no more than 13, no more than 12, no more than 11, no more than 10, no more than 9, no more than 8, no more than 7, no more than 6, no more than 5, no more than 4, no more than 3, no more than 2, or no more than 1 murine amino acid residues, or comprises no murine amino acid residue.
In some preferred embodiments, the heavy chain variable region of the antibody according to the invention has an amino acid sequence identity of at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% with a heavy chain variable region selected from:
heavy chain variable regions set forth in SEQ ID NOs: 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278 and 279.
In some preferred embodiments, the heavy chain variable region of the antibody according to the invention is selected from the heavy chain variable region set forth in any one of SEQ ID NOs: 11-92 and 263-279.
In some preferred embodiments, the light chain variable region of the antibody according to the invention has an amino acid sequence identity of at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% with a light chain variable region selected from:
light chain variable regions set forth in SEQ ID NOs: 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307 and 308.
In some preferred embodiments, the light chain variable region of the antibody according to the invention is selected from the light chain variable region set forth in any one of SEQ ID NOs: 186-214 and 298-308.
In some preferred embodiments, the antibody according to the invention comprises the heavy chain variable region as defined above and the light chain variable region as defined above.
In some preferred embodiments, the antibody according to the invention comprises:
(1) VH as set forth in SEQ ID NO: 11 and VL as set forth in SEQ ID NO: 186;
(2) VH as set forth in SEQ ID NO: 16 and VL as set forth in SEQ ID NO: 187;
(3) VH as set forth in SEQ ID NO: 14 and VL as set forth in SEQ ID NO: 187;
(4) VH as set forth in SEQ ID NO: 72 and VL as set forth in SEQ ID NO: 201;
(5) VH as set forth in SEQ ID NO: 71 and VL as set forth in SEQ ID NO: 199;
(6) VH as set forth in SEQ ID NO: 17 and VL as set forth in SEQ ID NO: 187;
(7) VH as set forth in SEQ ID NO: 31 and VL as set forth in SEQ ID NO: 187;
(8) VH as set forth in SEQ ID NO: 69 and VL as set forth in SEQ ID NO: 189;
(9) VH as set forth in SEQ ID NO: 44 and VL as set forth in SEQ ID NO: 187;
(10) VH as set forth in SEQ ID NO: 73 and VL as set forth in SEQ ID NO: 202;
(11) VH as set forth in SEQ ID NO: 32 and VL as set forth in SEQ ID NO: 187;
(12) VH as set forth in SEQ ID NO: 77 and VL as set forth in SEQ ID NO: 206;
(13) VH as set forth in SEQ ID NO: 45 and VL as set forth in SEQ ID NO: 187;
(14) VH as set forth in SEQ ID NO: 74 and VL as set forth in SEQ ID NO: 209;
(15) VH as set forth in SEQ ID NO: 47 and VL as set forth in SEQ ID NO: 187;
(16) VH as set forth in SEQ ID NO: 91 and VL as set forth in SEQ ID NO: 205;
(17) VH as set forth in SEQ ID NO: 73 and VL as set forth in SEQ ID NO: 205;
(18) VH as set forth in SEQ ID NO: 36 and VL as set forth in SEQ ID NO: 187;
(19) VH as set forth in SEQ ID NO: 36 and VL as set forth in SEQ ID NO: 189;
(20) VH as set forth in SEQ ID NO: 55 and VL as set forth in SEQ ID NO: 192;
(21) VH as set forth in SEQ ID NO: 46 and VL as set forth in SEQ ID NO: 187;
(22) VH as set forth in SEQ ID NO: 74 and VL as set forth in SEQ ID NO: 202;
(23) VH as set forth in SEQ ID NO: 92 and VL as set forth in SEQ ID NO: 200;
(24) VH as set forth in SEQ ID NO: 76 and VL as set forth in SEQ ID NO: 204;
(25) VH as set forth in SEQ ID NO: 42 and VL as set forth in SEQ ID NO: 187;
(26) VH as set forth in SEQ ID NO: 48 and VL as set forth in SEQ ID NO: 187;
(27) VH as set forth in SEQ ID NO: 20 and VL as set forth in SEQ ID NO: 187;
(28) VH as set forth in SEQ ID NO: 49 and VL as set forth in SEQ ID NO: 187;
(29) VH as set forth in SEQ ID NO: 18 and VL as set forth in SEQ ID NO: 187;
(30) VH as set forth in SEQ ID NO: 24 and VL as set forth in SEQ ID NO: 187;
(31) VH as set forth in SEQ ID NO: 19 and VL as set forth in SEQ ID NO: 187;
(32) VH as set forth in SEQ ID NO: 25 and VL as set forth in SEQ ID NO: 187;
(33) VH as set forth in SEQ ID NO: 21 and VL as set forth in SEQ ID NO: 187;
(34) VH as set forth in SEQ ID NO: 27 and VL as set forth in SEQ ID NO: 187;
(35) VH as set forth in SEQ ID NO: 22 and VL as set forth in SEQ ID NO: 187;
(36) VH as set forth in SEQ ID NO: 29 and VL as set forth in SEQ ID NO: 187;
(37) VH as set forth in SEQ ID NO: 12 and VL as set forth in SEQ ID NO: 187;
(38) VH as set forth in SEQ ID NO: 30 and VL as set forth in SEQ ID NO: 187;
(39) VH as set forth in SEQ ID NO: 33 and VL as set forth in SEQ ID NO: 187;
(40) VH as set forth in SEQ ID NO: 34 and VL as set forth in SEQ ID NO: 187;
(41) VH as set forth in SEQ ID NO: 35 and VL as set forth in SEQ ID NO: 187;
(42) VH as set forth in SEQ ID NO: 23 and VL as set forth in SEQ ID NO: 187;
(43) VH as set forth in SEQ ID NO: 75 and VL as set forth in SEQ ID NO: 203;
(44) VH as set forth in SEQ ID NO: 40 and VL as set forth in SEQ ID NO: 187;
(45) VH as set forth in SEQ ID NO: 37 and VL as set forth in SEQ ID NO: 187;
(46) VH as set forth in SEQ ID NO: 13 and VL as set forth in SEQ ID NO: 187;
(47) VH as set forth in SEQ ID NO: 15 and VL as set forth in SEQ ID NO: 187;
(48) VH as set forth in SEQ ID NO: 38 and VL as set forth in SEQ ID NO: 187;
(49) VH as set forth in SEQ ID NO: 41 and VL as set forth in SEQ ID NO: 187;
(50) VH as set forth in SEQ ID NO: 39 and VL as set forth in SEQ ID NO: 187;
(51) VH as set forth in SEQ ID NO: 43 and VL as set forth in SEQ ID NO: 187;
(52) VH as set forth in SEQ ID NO: 78 and VL as set forth in SEQ ID NO: 205;
(53) VH as set forth in SEQ ID NO: 72 and VL as set forth in SEQ ID NO: 205;
(54) VH as set forth in SEQ ID NO: 26 and VL as set forth in SEQ ID NO: 187;
(55) VH as set forth in SEQ ID NO: 28 and VL as set forth in SEQ ID NO: 187;
(56) VH as set forth in SEQ ID NO: 55 and VL as set forth in SEQ ID NO: 194;
(57) VH as set forth in SEQ ID NO: 70 and VL as set forth in SEQ ID NO: 198;
(58) VH as set forth in SEQ ID NO: 55 and VL as set forth in SEQ ID NO: 195;
(59) VH as set forth in SEQ ID NO: 55 and VL as set forth in SEQ ID NO: 197;
(60) VH as set forth in SEQ ID NO: 55 and VL as set forth in SEQ ID NO: 196;
(61) VH as set forth in SEQ ID NO: 90 and VL as set forth in SEQ ID NO: 187;
(62) VH as set forth in SEQ ID NO: 51 and VL as set forth in SEQ ID NO: 188;
(63) VH as set forth in SEQ ID NO: 54 and VL as set forth in SEQ ID NO: 190;
(64) VH as set forth in SEQ ID NO: 83 and VL as set forth in SEQ ID NO: 208;
(65) VH as set forth in SEQ ID NO: 79 and VL as set forth in SEQ ID NO: 190;
(66) VH as set forth in SEQ ID NO: 85 and VL as set forth in SEQ ID NO: 190;
(67) VH as set forth in SEQ ID NO: 62 and VL as set forth in SEQ ID NO: 189;
(68) VH as set forth in SEQ ID NO: 62 and VL as set forth in SEQ ID NO: 193;
(69) VH as set forth in SEQ ID NO: 66 and VL as set forth in SEQ ID NO: 189;
(70) VH as set forth in SEQ ID NO: 66 and VL as set forth in SEQ ID NO: 193;
(71) VH as set forth in SEQ ID NO: 64 and VL as set forth in SEQ ID NO: 189;
(72) VH as set forth in SEQ ID NO: 64 and VL as set forth in SEQ ID NO: 193;
(73) VH as set forth in SEQ ID NO: 67 and VL as set forth in SEQ ID NO: 189;
(74) VH as set forth in SEQ ID NO: 67 and VL as set forth in SEQ ID NO: 193;
(75) VH as set forth in SEQ ID NO: 65 and VL as set forth in SEQ ID NO: 193;
(76) VH as set forth in SEQ ID NO: 63 and VL as set forth in SEQ ID NO: 193;
(77) VH as set forth in SEQ ID NO: 82 and VL as set forth in SEQ ID NO: 189;
(78) VH as set forth in SEQ ID NO: 82 and VL as set forth in SEQ ID NO: 193;
(79) VH as set forth in SEQ ID NO: 60 and VL as set forth in SEQ ID NO: 189;
(80) VH as set forth in SEQ ID NO: 60 and VL as set forth in SEQ ID NO: 193;
(81) VH as set forth in SEQ ID NO: 56 and VL as set forth in SEQ ID NO: 189;
(82) VH as set forth in SEQ ID NO: 56 and VL as set forth in SEQ ID NO: 193;
(83) VH as set forth in SEQ ID NO: 61 and VL as set forth in SEQ ID NO: 189;
(84) VH as set forth in SEQ ID NO: 61 and VL as set forth in SEQ ID NO: 193;
(85) VH as set forth in SEQ ID NO: 57 and VL as set forth in SEQ ID NO: 189;
(86) VH as set forth in SEQ ID NO: 57 and VL as set forth in SEQ ID NO: 193;
(87) VH as set forth in SEQ ID NO: 58 and VL as set forth in SEQ ID NO: 189;
(88) VH as set forth in SEQ ID NO: 58 and VL as set forth in SEQ ID NO: 193;
(89) VH as set forth in SEQ ID NO: 59 and VL as set forth in SEQ ID NO: 189;
(90) VH as set forth in SEQ ID NO: 59 and VL as set forth in SEQ ID NO: 193;
(91) VH as set forth in SEQ ID NO: 68 and VL as set forth in SEQ ID NO: 189;
(92) VH as set forth in SEQ ID NO: 53 and VL as set forth in SEQ ID NO: 191;
(93) VH as set forth in SEQ ID NO: 55 and VL as set forth in SEQ ID NO: 199;
(94) VH as set forth in SEQ ID NO: 55 and VL as set forth in SEQ ID NO: 200;
(95) VH as set forth in SEQ ID NO: 53 and VL as set forth in SEQ ID NO: 187;
(96) VH as set forth in SEQ ID NO: 52 and VL as set forth in SEQ ID NO: 189;
(97) VH as set forth in SEQ ID NO: 84 and VL as set forth in SEQ ID NO: 210;
(98) VH as set forth in SEQ ID NO: 84 and VL as set forth in SEQ ID NO: 212;
(99) VH as set forth in SEQ ID NO: 50 and VL as set forth in SEQ ID NO: 187;
(100) VH as set forth in SEQ ID NO: 80 and VL as set forth in SEQ ID NO: 207;
(101) VH as set forth in SEQ ID NO: 88 and VL as set forth in SEQ ID NO: 214;
(102) VH as set forth in SEQ ID NO: 52 and VL as set forth in SEQ ID NO: 189;
(103) VH as set forth in SEQ ID NO: 89 and VL as set forth in SEQ ID NO: 212;
(104) VH as set forth in SEQ ID NO: 81 and VL as set forth in SEQ ID NO: 187;
(105) VH as set forth in SEQ ID NO: 84 and VL as set forth in SEQ ID NO: 211;
(106) VH as set forth in SEQ ID NO: 86 and VL as set forth in SEQ ID NO: 190;
(107) VH as set forth in SEQ ID NO: 87 and VL as set forth in SEQ ID NO: 213;
(108) VH as set forth in SEQ ID NO: 72 and VL as set forth in SEQ ID NO: 202;
(109) VH as set forth in SEQ ID NO: 72 and VL as set forth in SEQ ID NO: 306;
(110) VH as set forth in SEQ ID NO: 72 and VL as set forth in SEQ ID NO: 200;
(111) VH as set forth in SEQ ID NO: 91 and VL as set forth in SEQ ID NO: 300;
(112) VH as set forth in SEQ ID NO: 91 and VL as set forth in SEQ ID NO: 200;
(113) VH as set forth in SEQ ID NO: 263 and VL as set forth in SEQ ID NO: 192;
(114) VH as set forth in SEQ ID NO: 264 and VL as set forth in SEQ ID NO: 205;
(115) VH as set forth in SEQ ID NO: 264 and VL as set forth in SEQ ID NO: 192;
(116) VH as set forth in SEQ ID NO: 264 and VL as set forth in SEQ ID NO: 201;
(117) VH as set forth in SEQ ID NO: 264 and VL as set forth in SEQ ID NO: 202;
(118) VH as set forth in SEQ ID NO: 265 and VL as set forth in SEQ ID NO: 205;
(119) VH as set forth in SEQ ID NO: 265 and VL as set forth in SEQ ID NO: 201;
(120) VH as set forth in SEQ ID NO: 265 and VL as set forth in SEQ ID NO: 202;
(121) VH as set forth in SEQ ID NO: 266 and VL as set forth in SEQ ID NO: 205;
(122) VH as set forth in SEQ ID NO: 266 and VL as set forth in SEQ ID NO: 192;
(123) VH as set forth in SEQ ID NO: 267 and VL as set forth in SEQ ID NO: 298;
(124) VH as set forth in SEQ ID NO: 268 and VL as set forth in SEQ ID NO: 299;
(125) VH as set forth in SEQ ID NO: 269 and VL as set forth in SEQ ID NO: 301;
(126) VH as set forth in SEQ ID NO: 270 and VL as set forth in SEQ ID NO: 302;
(127) VH as set forth in SEQ ID NO: 271 and VL as set forth in SEQ ID NO: 202;
(128) VH as set forth in SEQ ID NO: 272 and VL as set forth in SEQ ID NO: 303;
(129) VH as set forth in SEQ ID NO: 273 and VL as set forth in SEQ ID NO: 304;
(130) VH as set forth in SEQ ID NO: 274 and VL as set forth in SEQ ID NO: 305;
(131) VH as set forth in SEQ ID NO: 275 and VL as set forth in SEQ ID NO: 200;
(132) VH as set forth in SEQ ID NO: 276 and VL as set forth in SEQ ID NO: 202;
(133) VH as set forth in SEQ ID NO: 277 and VL as set forth in SEQ ID NO: 307;
(134) VH as set forth in SEQ ID NO: 278 and VL as set forth in SEQ ID NO: 308;
or
(135) VH as set forth in SEQ ID NO: 279 and VL as set forth in SEQ ID NO: 202.
In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention can specifically bind to HBsAg, neutralize HBV virulence, and/or reduce the serum level of HBV DNA and/or HBsAg in a subject.
In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention is selected from the group consisting of scFv, Fab, Fab′, (Fab′)2, Fv fragment, diabody, bispecific antibody, and polyspecific antibody. Particularly preferably, the antibody or an antigen binding fragment thereof according to the invention is a scFv antibody.
In some preferred embodiments, the antibody or an antigen binding fragment thereof according to the invention is an antibody of IgG1 isotype or an antigen binding fragment thereof. For example, the antibody or an antigen binding fragment thereof according to the invention may be an antibody of IgG1, IgG2 or IgG4 isotype, or an antigen binding fragment thereof.
In another aspect, the invention provides an isolated nucleic acid molecule, comprising a nucleotide sequence encoding the antibody or an antigen binding fragment thereof according to the invention, or the heavy chain variable region and/or light chain variable region thereof.
In another aspect, the invention provides a vector (e.g. a cloning vector or an expression vector), comprising the isolated nucleic acid molecule according to the invention.
In another aspect, the invention provides a host cell, comprising the isolated nucleic acid molecule according to the invention or the vector according to the invention.
In another aspect, provided is a method for preparing the antibody or an antigen binding fragment thereof according to the invention, comprising, culturing the host cell according to the invention under a condition allowing expression of the antibody or an antigen binding fragment thereof, and recovering the antibody or an antigen binding fragment thereof from a culture of the cultured host cell.
In another aspect, the invention provides a kit, comprising the antibody or an antigen binding fragment thereof according to the invention. In a preferred embodiment, the antibody or an antigen binding fragment thereof according to the invention further comprises a detectable marker. In a preferred embodiment, the kit further comprises a second antibody, which specifically recognizes the antibody or an antigen binding fragment thereof according to the invention. Preferably, the second antibody further comprises a detectable marker. Such detectable markers, which are well known by a person skilled in the art, include, but are not limited to, radioisotope, fluorescent substance, luminescent substance, chromophoric substance and enzyme (e.g. horseradish peroxidase), etc.
In another aspect, the invention provides a method for detecting the presence or level of HBsAg protein in a sample, comprising using the antibody or an antigen binding fragment thereof according to the invention. In a preferred embodiment, the antibody or an antigen binding fragment thereof according to the invention further comprises a detectable marker. In another preferred embodiment, the method further comprises, using a second antibody carrying a detectable marker to detect the antibody or an antigen binding fragment thereof according to the invention. The method may be used for diagnostic purpose or for non-diagnostic purpose (for example, said sample is a cell sample, rather than a sample from a patient).
In another aspect, the invention provides a method for diagnosing whether a subject is infected by HBV, comprising: using the antibody or an antigen binding fragment thereof according to the invention to detect the presence of HBsAg protein in a sample from the subject. In a preferred embodiment, the antibody or an antigen binding fragment thereof according to the invention further comprises a detectable marker. In another preferred embodiment, the method further comprises, using a second antibody carrying a detectable marker to detect the antibody or an antigen binding fragment thereof according to the invention.
In another aspect, provided is use of the antibody or an antigen binding fragment thereof according to the invention in the manufacture of a kit for detecting the presence or level of HBsAg in a sample or for diagnosing whether a subject is infected by HBV.
The antibody or an antigen binding fragment thereof according to the invention can be used for preventing or treating HBV infection or a disease associated with HBV infection (such as Hepatitis B) in a subject (such as human), for neutralizing HBV virulence in vitro or in a subject (such as human), and for reducing the serum level of HBV DNA and/or HBsAg in a subject (such as human).
Therefore, in another aspect, the invention provides a pharmaceutical composition, comprising the antibody or an antigen binding fragment thereof according to the invention, and a pharmaceutically acceptable carrier and/or excipient. In a preferred embodiment, the pharmaceutical composition according to the invention may further comprise an additional pharmaceutically active agent. In a preferred embodiment, the additional pharmaceutically active agent is an agent for preventing or treating HBV infection or a disease associated with HBV infection (such as Hepatitis B), for example, interferon-type agents, such as interferon or pegylated interferon.
In another aspect, provided is use of the antibody or an antigen binding fragment thereof according to the invention or the pharmaceutical composition according to the invention in the manufacture of a medicament for preventing or treating HBV infection or a disease associated with HBV infection (such as Hepatitis B) in a subject (such as human), for neutralizing HEY virulence in vitro or in a subject (such as human), and/or for reducing the serum level of HBV DNA and/or HBsAg in a subject (such as human).
In another aspect, the invention provides a method for preventing or treating HBV infection or a disease associated with HBV infection (such as Hepatitis B) in a subject (such as human), for neutralizing HBV virulence in a subject (such as human), and/or for reducing the serum level of HBV DNA and/or HBsAg in a subject (such as human), comprising, administering to a subject in need thereof an effective amount of the antibody or an antigen binding fragment thereof according to the invention or the pharmaceutical composition according to the invention.
The medicament and pharmaceutical composition provided in the invention may be used alone or in combination, or may be used in combination with an additional pharmaceutically active agent (for example, other antiviral agents, e.g. interferon-type agents, such as interferon or pegylated interferon).
The embodiments of the invention are described in detail by reference to the following drawings and examples. However, a person skilled in the art would understand that the following drawings and examples are intended for illustrating the invention only, rather than defining the scope of the invention. According to the detailed description of the following drawings and preferred embodiments, various purposes and advantages of the invention are obvious for a person skilled in the art.